Makefile: Clean up empty redirected file on failure

If the preprocessor fails for any reason then an empty or partially
processed watch.py file is created which will satisfy the dependency
checks in any later invocation of make which can silently break the
build. Cleaning up on failure prevents this from happening.

Signed-off-by: Daniel Thompson <daniel@redfelineninja.org.uk>

0 files changed, 0 insertions, 0 deletions